1. Field of the Disclosure
This disclosure relates to a DC power supply system, which is provided with a rectifier and a charger, and a control method thereof.
2. Discussion of the Background Art
There has been known a DC backup power supply system which charges a storage battery while supplying a DC current to a load (for example, see Japanese Patent Application Laid-Open No. 2009-296719).
In general, in order to extend a life of a storage battery, it is preferable that the storage battery is charged at a constant current and an electric current is prevented from being output from the storage battery as much as possible. In the DC backup power supply system disclosed in Japanese Patent Application Laid-Open No. 2009-296719, an output current output from a charger is controlled to be kept constant until an output voltage of a storage battery reaches a predetermined value during charging of the storage battery. Thus, in the DC backup power supply system disclosed in Japanese Patent Application Laid-Open No. 2009-296719, when an assist current is required to be supplied from the storage battery to a load due to, for example, overload during charging of the storage battery, there is a problem that the storage battery cannot be charged with a constant current.